The present exemplary embodiment is directed to printing, and more particularly to printing with hand-held wand printers.
For printing a stored image on a target medium such as paper, a desktop printer or portable printer has typically been employed. In such devices, the medium is fed past an ink-jet head, laser or other printing mechanism within the device so that image data is reproduced on the target. Thus, even though printers may be portable, such devices are not suitable for printing on surfaces that cannot be fed through the device. To address this issue, printers commonly referred to as hand-held or hand-propelled wand printers have been investigated. These printers are capable of printing on targets, such as “found paper”, which is understood to mean the printer will print on paper which is not within the printer itself, such as paper in a binder, on envelopes, scraps of paper, etc.
One such hand-held printer is disclosed in U.S. Pat. No. 5,927,872 to Yamada. This printer has optical sensors for tracking positions of the hand-held printer relative to the surface of a print medium during a printing process. The change in position of the hand-held printer during the printing process is monitored in real time using navigation information generated by the optical sensors. Images of the surface of the print medium are captured at fixed time intervals. The optical sensors may detect printed features or slight pattern variations on the print medium, such as papers fibers or illumination patterns from reflective features and shadowed areas between raised features. Such features are used as references for determining the movement of the hand-held printer.
Another example of a hand-held wand printing device is disclosed in U.S. Pat. No. 6,517,266 to Saund. This hand-held printer system is designed for printing a stored image onto a surface. In particular, various embodiments are adapted for hand-held printing onto the surface of a whiteboard. The system includes a marking mechanism having at least one printhead. A global position sensing system senses a position of the at least one printhead, and a control mechanism actuates the at least one printhead based on the sensed position. In other embodiments, the system includes a local position sensing system that senses a position of the at least one printhead relative to a drawing surface.
Yet another hand-held printer is described in Published U.S. patent application No. 2003/0051615 to Denoue et al. This application sets forth a method and system for position-aware freeform printing in which a source image space in a source medium and a target image space in a target medium are specified. A selected image in the source image space is copied and/or optionally processed and transferred to the target image space. A controller captures the selected source image and stores the image in a memory. The image is optionally processed, and the processed and optionally formatted image is output. The controller may format the processed image to fit into the target image space by controlling the rendering of the processed image onto the target medium as the printing device is moved over the target image space in a freeform direction. The controller predicts the freeform direction that the print head will travel by detecting the motion previously traveled and adjusting the image to compensate for the predicted freeform direction.
Two U.S. patents, U.S. Pat. Nos. 5,593,236 and 5,988,900 to Bobry, disclose a hand-held and self-contained electronic printing apparatus for printing indicia on a medium disposed outside the apparatus, including a housing that can be manually positioned adjacent a surface of the medium and manually swept across a printing area on the medium during a printing sequence. A printer is disposed in the housing and has a printhead with a plurality of print elements such as ink jet nozzles for printing indicia in a selectable pattern of dots on the medium within the printing area. An electronic control circuit is disposed in the housing for controlling the printer to print indicia on the medium during a printing sequence, the control circuit having compensation for reducing image distortion based on detecting position of the nozzles during a printing sequence.
The above-noted material describes various beneficial aspects of hand-held printing. However, these systems produce an image whose orientation is determined by the initial orientation of the printer when the print swipe commences. Many uses of hand held printers involve casual printing of relatively compact regions. For example, printing a reminder note onto a notepad. For such uses, accurate alignment of the printed material with the target page is not also a priority, although at times such alignment may be desired. At other times, a user may wish to print long stretches of text, maps, or graphic art and in these cases aligned with the page is particularly appropriate.
The known art does not take into account situations where the target (e.g., page onto which the image or data is to be printed is skewed or otherwise aligned in a position other than anticipated.
For example, while Yamada '872 and Bobry '236 and '900 disclose adjusting output for movement of the printer in a curved path as opposed to a straight line, these and the other known systems do not discuss situations where the target onto which the material is to be printed is itself misaligned.